Diseases and Contaminants in Waterfowl

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Waterfowl are common reservoirs for a variety of avian diseases and can suffer significant mortality from certain pathogens. Additionally, waterfowl are exposed to naturally occurring and human sources of contaminants. Research at the USGS Alaska Science Center on disease and contaminants in waterfowl strengthens the efficiency and effectiveness of disease surveillance across North America. Results from research also provides information on existing and emerging threats to waterfowl populations and to the humans that rely on these species for subsistence and sport harvest. The USGS Alaska Science Center uses field and laboratory investigations, genetic and band-recovery to: identify sources and impacts of disease and contaminants, identify routes of spread based on migration patterns, and to identify priority areas for future sampling of contaminants and surveillance for disease.

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Man releasing duck in Japan. He wears a face mask for protection from disease

USGS Alaska Science Center biologists Andrew Ramey and John Reed travelled to Japan to capture spring staging northern pintail ducks in collaboration with researchers from the University of Tokyo, Satoyama Research Society, and Kucharo Lake Waterfowl Observatory. This capture effort will further inform the role of migratory birds in the movement of avian diseases, the genetic diversity of avian pathogens, and the optimization of surveillance plans for detection of emerging wildlife disease in North America.​​​​​​​(Credit: John Reed, USGS. Public domain.)

Waterfowl are the natural reservoir for several viruses, including avian influenza and avian paramyxovirus (which can cause Newcastle disease in poultry). In many cases, these viruses cause no obvious signs of disease to the waterfowl host, but in some cases certain viruses have caused large-scale mortalities among waterfowl species. Research at the USGS Alaska Science Center on waterfowl viruses seeks to understand the general prevalence in wild populations, genetic characteristics to inform origins and evolutionary change, and to determine the role of wild birds in the spread of viruses across the landscape during migration.

Blood Parasites

Waterfowl are frequently infected by blood parasites which are spread by insect vectors. Infections may lead to disease and mortalities in wild birds, but most infections are believed to be relatively benign. In North America, blood parasite (or hematozoa) infection in wild birds varies across the landscape and among taxa. Past studies have generally found low prevalence of blood parasites in taxa sampled at northern arctic and sub-arctic tundra landscapes in contrast to higher rates of infection detected in birds sampled throughout forested habitats of Alaska and northern Canada. USGS Alaska Science Center research on blood parasites in waterfowl is examining the general prevalence of these pathogens in wild birds, if infections by these pathogens is causing a demographic impact to species, and if wild birds are spreading these pathogens between and within continents during migration.


Waterfowl are susceptible to infection by different types of bacteria, some of which cause mortality and others which are relatively benign. USGS Alaska Science Center research on waterfowl bacteria is focusing on understanding the prevalence in wild species, demographic impacts, and using genetic markers to determine the origins of bacterial strains. Recent USGS research has focused on bacteria associated with avian cholera (Pasteurella multocida), E. coli, and a strain of Neisseria. The USGS Alaska Science Center is also conducting research to determine if waterfowl and other bird species are carrying and redistributing strains of antibiotic resistant bacteria.


The USGS has studied presence and possible impacts of lead in waterfowl for decades. Two notable species where research has been conducted are the spectacled eider and the tundra swan. Spectacled eider populations in western Alaska declined rapidly through the 1980s and low adult female survival was suggested as the likely cause of the decline. In 1995, USGS research identified lead poisoning, resulting from ingestion of spent shot, as a cause of mortality in Spectacled Eiders. Since then, USGS research has examined lead-exposure rates of spectacled eiders and other waterfowl to determine presence and possible impacts to birds. In another study, USGS measured blood lead concentrations in tundra swans at five locations in Alaska, representing birds that winter in both the Pacific Flyway and Atlantic Flyway. Lead levels were generally low ( < 0.2 μg/ml) in swans across all breeding areas and varied significantly across the five breeding areas, with highest concentrations in birds on the North Slope of Alaska (wintering in the Atlantic Flyway), and lowest in birds from the lower Alaska Peninsula that rarely migrate south for winter.

Other Contaminants

Waterfowl species are broadly distributed across the landscape, undergo long-distance migrations that take them through a variety of habitats and landscape types, and often highly concentrated at certain times of the year. These behaviors make them susceptible to exposure to natural and human-derived contaminants. USGS Alaska Science Center research examines the levels of these contaminants in wild waterfowl and also the demographic impacts of these elements to bird populations.

Oil Spills

Many waterfowl species (particularly sea ducks) concentrate in coastal marine areas during several months of the year, often in sheltered bays that are also used by marine vessel traffic and sea food processing facilities. The USGS Alaska Science Center waterfowl research program examines the magnitude, duration, and effects of oil to wild bird population in these marine areas.